package demo1;

public class Computer {
    public void powerOn(){
        System.out.println("打开电脑");
    }

    public void powerOff(){
        System.out.println("关闭电脑");
    }

    public void useService(USB usb){
        usb.openDevice();
        if (usb instanceof  Mouse){
            Mouse mouse = (Mouse)usb;
            mouse.click();
        } else if (usb instanceof KeyBoard) {
            KeyBoard keyBoard = (KeyBoard)usb;
            keyBoard.input();
        }
        usb.closeDevice();
    }
}
